Difference between revisions of "cpp/container/list"

Latest revision as of 20:56, 2 August 2024

Defined in header `<list>`
template< class T, class Allocator = std::allocator<T> > class list;	(1)
namespace pmr { template< class T > using list = std::list<T, std::pmr::polymorphic_allocator<T>>; }	(2)	(since C++17)

std::list is a container that supports constant time insertion and removal of elements from anywhere in the container. Fast random access is not supported. It is usually implemented as a doubly-linked list. Compared to std::forward_list this container provides bidirectional iteration capability while being less space efficient.

Adding, removing and moving the elements within the list or across several lists does not invalidate the iterators or references. An iterator is invalidated only when the corresponding element is deleted.

std::list meets the requirements of Container, AllocatorAwareContainer, SequenceContainer and ReversibleContainer.

The requirements that are imposed on the elements depend on the actual operations performed on the container. Generally, it is required that element type meets the requirements of Erasable, but many member functions impose stricter requirements. This container (but not its members) can be instantiated with an incomplete element type if the allocator satisfies the allocator completeness requirements.

Feature-test macro	Value	Std	Feature
`__cpp_lib_incomplete_container_elements`	201505L	(C++17)	Minimal incomplete type support

(since C++17)

[edit]

Allocator - An allocator that is used to acquire/release memory and to construct/destroy the elements in that memory. The type must meet the requirements of Allocator. The behavior is undefined(until C++20)The program is ill-formed(since C++20) if Allocator::value_type is not the same as T.[edit]

[edit] Member types

Member type Definition

value_type T[edit]

allocator_type Allocator[edit]

size_type Unsigned integer type (usually std::size_t)[edit]

difference_type Signed integer type (usually std::ptrdiff_t)[edit]

reference value_type&[edit]

const_reference const value_type&[edit]

pointer

`Allocator::pointer`	(until C++11)
std::allocator_traits<Allocator>::pointer	(since C++11)

[edit]

const_pointer

`Allocator::const_pointer`	(until C++11)
std::allocator_traits<Allocator>::const_pointer	(since C++11)

[edit]

iterator LegacyBidirectionalIterator to value_type[edit]

const_iterator LegacyBidirectionalIterator to const value_type[edit]

reverse_iterator std::reverse_iterator<iterator>[edit]

const_reverse_iterator std::reverse_iterator<const_iterator>[edit]

[edit] Member functions

(constructor)	constructs the `list` (public member function) [edit]
(destructor)	destructs the `list` (public member function) [edit]
operator=	assigns values to the container (public member function) [edit]
assign	assigns values to the container (public member function) [edit]
assign_range (C++23)	assigns a range of values to the container (public member function) [edit]
get_allocator	returns the associated allocator (public member function) [edit]
Element access
front	access the first element (public member function) [edit]
back	access the last element (public member function) [edit]
Iterators
begincbegin (C++11)	returns an iterator to the beginning (public member function) [edit]
endcend (C++11)	returns an iterator to the end (public member function) [edit]
rbegincrbegin (C++11)	returns a reverse iterator to the beginning (public member function) [edit]
rendcrend (C++11)	returns a reverse iterator to the end (public member function) [edit]
Capacity
empty	checks whether the container is empty (public member function) [edit]
size	returns the number of elements (public member function) [edit]
max_size	returns the maximum possible number of elements (public member function) [edit]
Modifiers
clear	clears the contents (public member function) [edit]
insert	inserts elements (public member function) [edit]
insert_range (C++23)	inserts a range of elements (public member function) [edit]
emplace (C++11)	constructs element in-place (public member function) [edit]
erase	erases elements (public member function) [edit]
push_back	adds an element to the end (public member function) [edit]
emplace_back (C++11)	constructs an element in-place at the end (public member function) [edit]
append_range (C++23)	adds a range of elements to the end (public member function) [edit]
pop_back	removes the last element (public member function) [edit]
push_front	inserts an element to the beginning (public member function) [edit]
emplace_front (C++11)	constructs an element in-place at the beginning (public member function) [edit]
prepend_range (C++23)	adds a range of elements to the beginning (public member function) [edit]
pop_front	removes the first element (public member function) [edit]
resize	changes the number of elements stored (public member function) [edit]
swap	swaps the contents (public member function) [edit]
Operations
merge	merges two sorted lists (public member function) [edit]
splice	moves elements from another `list` (public member function) [edit]
removeremove_if	removes elements satisfying specific criteria (public member function) [edit]
reverse	reverses the order of the elements (public member function) [edit]
unique	removes consecutive duplicate elements (public member function) [edit]
sort	sorts the elements (public member function) [edit]

[edit] Non-member functions

operator==operator!=operator<operator<=operator>operator>=operator<=> (removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)	lexicographically compares the values of two `list`s (function template) [edit]
std::swap(std::list)	specializes the std::swap algorithm (function template) [edit]
erase(std::list)erase_if(std::list) (C++20)	erases all elements satisfying specific criteria (function template) [edit]

Deduction guides

(since C++17)

[edit] Notes

Feature-test macro	Value	Std	Feature
`__cpp_lib_containers_ranges`	202202L	(C++23)	Ranges construction and insertion for containers

[edit] Example

Run this code

#include <algorithm>
#include <iostream>
#include <list>
 
int main()
{
    // Create a list containing integers
    std::list<int> l = {7, 5, 16, 8};
 
    // Add an integer to the front of the list
    l.push_front(25);
    // Add an integer to the back of the list
    l.push_back(13);
 
    // Insert an integer before 16 by searching
    auto it = std::find(l.begin(), l.end(), 16);
    if (it != l.end())
        l.insert(it, 42);
 
    // Print out the list
    std::cout << "l = { ";
    for (int n : l)
        std::cout << n << ", ";
    std::cout << "};\n";
}

Output:

l = { 25, 7, 5, 42, 16, 8, 13, };

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 230	C++98	`T` was not required to be CopyConstructible (an element of type `T` might not be able to be constructed)	`T` is also required to be CopyConstructible
LWG 276	C++98	`T` was always required to be CopyAssignable	only required if `operator=` or `assign` is instantiated with `T`

[edit] See also

forward_list

(C++11)

singly-linked list
(class template) [edit]

@@ Line 1: / Line 1: @@
 {{cpp/title|list}}
 {{cpp/container/list/navbar}}
-{{ddcl | header=list |
+{{dcl begin}}
+{{dcl header|list}}
+{{dcl|num=1|1=
 template<
      class T,
-     class Allocator {{=}} std::allocator<T>
+     class Allocator = std::allocator<T>
 > class list;
 }}
+{{dcl|num=2|since=c++17|1=
+namespace pmr {
+    template< class T >
+    using list = std::list<T, std::pmr::polymorphic_allocator<T>>;
+}
+}}
+{{dcl end}}
-{{tt|std::list}} is a container that supports constant time insertion and removal of elements from anywhere in the container. Fast random access is not supported. It is usually implemented as double-linked list. Compared to {{lc|std::forward_list}} this container provides bidirectional iteration capability while being less space efficient.
+{{tt|std::list}} is a container that supports constant time insertion and removal of elements from anywhere in the container. Fast random access is not supported. It is usually implemented as a doubly-linked list. Compared to {{lc|std::forward_list}} this container provides bidirectional iteration capability while being less space efficient.
-Addition, removal and moving the elements within the list or across several lists does not invalidate the iterators. An iterator is invalidated only when the corresponding element is deleted.
+Adding, removing and moving the elements within the list or across several lists does not invalidate the iterators or references. An iterator is invalidated only when the corresponding element is deleted.
-{{tt|std::list}} meets the requirements of {{concept|Container}}, {{concept|AllocatorAwareContainer}}, {{concept|SequenceContainer}} and {{concept|ReversibleContainer}}.
+{{tt|std::list}} meets the requirements of {{named req|Container}}, {{named req|AllocatorAwareContainer}}, {{named req|SequenceContainer}} and {{named req|ReversibleContainer}}.
 ===Template parameters===
 {{par begin}}
-{{par inc | cpp/container/param list T | deque}}
+{{par inc|cpp/container/param list T|list}}
-{{par inc | cpp/container/param list Allocator | deque}}
+{{par inc|cpp/container/param list Allocator|list}}
 {{par end}}
 ===Member types===
 {{dsc begin}}
-{{dsc hitem | Member type | Definition}}
+{{dsc hitem|Member type|Definition}}
-{{dsc inc | cpp/container/dsc value_type | list}}
+{{dsc inc|cpp/container/dsc value_type|list}}
-{{dsc inc | cpp/container/dsc allocator_type | list}}
+{{dsc inc|cpp/container/dsc allocator_type|list}}
-{{dsc inc | cpp/container/dsc size_type | list}}
+{{dsc inc|cpp/container/dsc size_type|list}}
-{{dsc inc | cpp/container/dsc difference_type | list}}
+{{dsc inc|cpp/container/dsc difference_type|list}}
-{{dsc inc | cpp/container/dsc reference | list}}
+{{dsc inc|cpp/container/dsc reference|list}}
-{{dsc inc | cpp/container/dsc const_reference | list}}
+{{dsc inc|cpp/container/dsc const_reference|list}}
-{{dsc inc | cpp/container/dsc pointer | list}}
+{{dsc inc|cpp/container/dsc pointer|list}}
-{{dsc inc | cpp/container/dsc const_pointer | list}}
+{{dsc inc|cpp/container/dsc const_pointer|list}}
-{{dsc inc | cpp/container/dsc iterator | list}}
+{{dsc inc|cpp/container/dsc iterator|list}}
-{{dsc inc | cpp/container/dsc const_iterator | list}}
+{{dsc inc|cpp/container/dsc const_iterator|list}}
-{{dsc inc | cpp/container/dsc reverse_iterator | list}}
+{{dsc inc|cpp/container/dsc reverse_iterator|list}}
-{{dsc inc | cpp/container/dsc const_reverse_iterator | list}}
+{{dsc inc|cpp/container/dsc const_reverse_iterator|list}}
 {{dsc end}}
 ===Member functions===
 {{dsc begin}}
-{{dsc inc | cpp/container/dsc constructor | list}}
+{{dsc inc|cpp/container/dsc constructor|list}}
-{{dsc inc | cpp/container/dsc destructor | list}}
+{{dsc inc|cpp/container/dsc destructor|list}}
-{{dsc inc | cpp/container/dsc operator{{=}} | list}}
+{{dsc inc|cpp/container/dsc operator{{=}}|list}}
-{{dsc inc | cpp/container/dsc assign | list}}
+{{dsc inc|cpp/container/dsc assign|list}}
-{{dsc inc | cpp/container/dsc get_allocator | list}}
+{{dsc inc|cpp/container/dsc assign_range|list}}
+{{dsc inc|cpp/container/dsc get_allocator|list}}
-{{dsc h2 | Element access}}
+{{dsc h2|Element access}}
-{{dsc inc | cpp/container/dsc front | list}}
+{{dsc inc|cpp/container/dsc front|list}}
-{{dsc inc | cpp/container/dsc back | list}}
+{{dsc inc|cpp/container/dsc back|list}}
-{{dsc h2 | Iterators}}
+{{dsc h2|Iterators}}
-{{dsc inc | cpp/container/dsc begin | list}}
+{{dsc inc|cpp/container/dsc begin|list}}
-{{dsc inc | cpp/container/dsc end | list}}
+{{dsc inc|cpp/container/dsc end|list}}
-{{dsc inc | cpp/container/dsc rbegin | list}}
+{{dsc inc|cpp/container/dsc rbegin|list}}
-{{dsc inc | cpp/container/dsc rend | list}}
+{{dsc inc|cpp/container/dsc rend|list}}
-{{dsc h2 | Capacity}}
+{{dsc h2|Capacity}}
-{{dsc inc | cpp/container/dsc empty | list}}
+{{dsc inc|cpp/container/dsc empty|list}}
-{{dsc inc | cpp/container/dsc size | list}}
+{{dsc inc|cpp/container/dsc size|list}}
-{{dsc inc | cpp/container/dsc max_size | list}}
+{{dsc inc|cpp/container/dsc max_size|list}}
-{{dsc h2 | Modifiers}}
+{{dsc h2|Modifiers}}
-{{dsc inc | cpp/container/dsc clear | list}}
+{{dsc inc|cpp/container/dsc clear|list}}
-{{dsc inc | cpp/container/dsc insert | list}}
+{{dsc inc|cpp/container/dsc insert|list}}
-{{dsc inc | cpp/container/dsc emplace | list}}
+{{dsc inc|cpp/container/dsc insert_range|list}}
-{{dsc inc | cpp/container/dsc erase | list}}
+{{dsc inc|cpp/container/dsc emplace|list}}
-{{dsc inc | cpp/container/dsc push_back | list}}
+{{dsc inc|cpp/container/dsc erase|list}}
-{{dsc inc | cpp/container/dsc emplace_back | list}}
+{{dsc inc|cpp/container/dsc push_back|list}}
-{{dsc inc | cpp/container/dsc pop_back | list}}
+{{dsc inc|cpp/container/dsc emplace_back|list}}
-{{dsc inc | cpp/container/dsc push_front | list}}
+{{dsc inc|cpp/container/dsc append_range|list}}
-{{dsc inc | cpp/container/dsc emplace_front | list}}
+{{dsc inc|cpp/container/dsc pop_back|list}}
-{{dsc inc | cpp/container/dsc pop_front | list}}
+{{dsc inc|cpp/container/dsc push_front|list}}
-{{dsc inc | cpp/container/dsc resize | list}}
+{{dsc inc|cpp/container/dsc emplace_front|list}}
-{{dsc inc | cpp/container/dsc swap | list}}
+{{dsc inc|cpp/container/dsc prepend_range|list}}
+{{dsc inc|cpp/container/dsc pop_front|list}}
+{{dsc inc|cpp/container/dsc resize|list}}
+{{dsc inc|cpp/container/dsc swap|list}}
-{{dsc h2 | Operations}}
+{{dsc h2|Operations}}
-{{dsc inc | cpp/container/dsc merge | list}}
+{{dsc inc|cpp/container/dsc merge|list}}
-{{dsc inc | cpp/container/dsc splice | list}}
+{{dsc inc|cpp/container/dsc splice|list}}
-{{dsc inc | cpp/container/dsc remove | list}}
+{{dsc inc|cpp/container/dsc remove|list}}
-{{dsc inc | cpp/container/dsc reverse | list}}
+{{dsc inc|cpp/container/dsc reverse|list}}
-{{dsc inc | cpp/container/dsc unique | list}}
+{{dsc inc|cpp/container/dsc unique|list}}
-{{dsc inc | cpp/container/dsc sort | list}}
+{{dsc inc|cpp/container/dsc sort|list}}
 {{dsc end}}
 ===Non-member functions===
 {{dsc begin}}
-{{dsc inc | cpp/container/dsc operator_cmp | list}}
+{{dsc inc|cpp/container/dsc operator_cmp|list}}
-{{dsc inc | cpp/container/dsc swap2 | list}}
+{{dsc inc|cpp/container/dsc swap2|list}}
+{{dsc inc|cpp/container/dsc erase seq|list}}
 {{dsc end}}
-[[de:cpp/container/list]]
+{{rrev|since=c++17|
-[[es:cpp/container/list]]
+==={{rl|deduction guides|Deduction guides}}===
-[[fr:cpp/container/list]]
+}}
-[[it:cpp/container/list]]
-[[ja:cpp/container/list]]
+===Notes===
-[[pt:cpp/container/list]]
+{{ftm begin|std=1|comment=1}}
-[[ru:cpp/container/list]]
+{{ftm|__cpp_lib_containers_ranges|value=202202L|std=C++23|Ranges construction and insertion for containers}}
-[[zh:cpp/container/list]]
+{{ftm end}}
+===Example===
+{{example
+|code=
+#include <algorithm>
+#include <iostream>
+#include <list>
+int main()
+{
+    // Create a list containing integers
+    std::list<int> l = {7, 5, 16, 8};
+    // Add an integer to the front of the list
+    l.push_front(25);
+    // Add an integer to the back of the list
+    l.push_back(13);
+    // Insert an integer before 16 by searching
+    auto it = std::find(l.begin(), l.end(), 16);
+    if (it != l.end())
+        l.insert(it, 42);
+    // Print out the list
+    std::cout << "l = { ";
+    for (int n : l)
+        std::cout << n << ", ";
+    std::cout << "};\n";
+}
+|output=
+l = { 25, 7, 5, 42, 16, 8, 13, };
+}}
+===Defect reports===
+{{dr list begin}}
+{{dr list item|wg=lwg|dr=230|std=C++98|before={{tt|T}} was not required to be {{named req|CopyConstructible}}<br>(an element of type {{tt|T}} might not be able to be constructed)|after={{tt|T}} is also required to<br>be {{named req|CopyConstructible}}}}
+{{dr list item|wg=lwg|dr=276|std=C++98|before={{tt|T}} was always required to be {{named req|CopyAssignable}}|after=only required if {{ltt|cpp/container/list/operator{{=}}}} or<br>{{ltt|cpp/container/list/assign}} is instantiated with {{tt|T}}}}
+{{dr list end}}
+===See also===
+{{dsc begin}}
+{{dsc inc|cpp/container/dsc forward_list}}
+{{dsc end}}
+{{langlinks|de|es|fr|it|ja|ko|pl|pt|ru|zh}}

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Difference between revisions of "cpp/container/list"

Latest revision as of 20:56, 2 August 2024

Contents

[edit] Template parameters

[edit] Member types

[edit] Member functions

Element access

Iterators

Capacity

Modifiers

Operations

[edit] Non-member functions

Deduction guides

[edit] Notes

[edit] Example

[edit] Defect reports

[edit] See also

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